When I flipped a rock in northern Arizona last week, I found these ants with the eggs and larvae.

Why do you think ants live under rocks? I have noticed they often have piles of eggs, larvae and pupae under rocks, particularly in cold climates. Do you think perhaps the rocks warm the ground and they are using them as heaters to keep the young ants warm?

Because they often live underground, we might not give as much thought to the nests constructed by ants. Dr. Walter Tschinkel has modified an older technique for looking at the structure of ant nests by pouring dental plaster into the tunnels, allowing it to dry and then digging up the nest, giving a negative-space impression of some truly impressive ant nests.

Dr. Walter Tschinkel’s Ant Castles can be found at the Florida State University. He's says that the ants can build the huge one at the bottom in just five days!